Trust, Trust, Trust.
I've always heard stories, either in biographies or interviews, of successful actors talking about their "break out" role. The story is most always the same. Their "break out" role was given to them after an audition in which they "let go". They were tired, had gotten the sides later than usual, didn't think they were going to get the part so they just said "f*** it". They didn't put too much energy in trying to "be" anything, or make the "right" choice.
And then they land the role! Because they were relaxed, and honest, and just doing their job. Not trying to prove themselves.
Today I had an audition that felt a lot like that! It's such a relief to be able to go into the audition room and just lay it out on the floor. Relax, be truthful, because what's the worst that happens?
You don't get the role and tomorrow you wake up to start working on the next audition. Trust yourself and let go in the audition room. That's the only way you can do your job.